Osteosarcoma: Our study with newly diagnosed localized and metastatic osteosarcoma continues to accrue patients, in collaboration with several other centers. The study is attempting to determine the value of dynamic MRI imaging (DEMRI) is predicting response to neoadjuvant chemotherapy. We now have data on this technique in 14 patients studied within the NCI. While the predictive value appears to be promising, we still need additional data before we can publish this work. We have also performed gene expression profiling analysis on these tumors in collaboration with Dr. Lau at Texas Children's Hospital and preliminary analysis suggests that profiles may allow us to cluster patients into "good" and "poor" prognosis prospectively, although once again additional data are required. There is also a suggestion that development of metastatic disease may be predictable based upon expression profiles of the primary tumor. We have now closed the high-dose chemotherapy with autologous stem cell rescue arm of this study, as we have now demonstrated that this intervention will not lead to a greater than 50% DFS in poor risk patients. Ewings Sarcoma: We await activation of an IRB approved study for a new salvage therapy for recurrent osteosarcoma and Ewing's sarcoma using a combination of sequential gemcitabine/docetaxel based on preliminary in vitro synergy and previous activity of the single agents. This study will be performed through a newly formed sarcoma consortium and is supported by Aventis and Lilly. We continue to accrue patients with newly diagnosed disease to evaluate the effectiveness of a long-acting G-CSF compound and have opened this study at several other institutions in an effort to complete accrual. Patients receive standard 5-drug chemotherapy and are randomized to receive standard or long-acting G-CSF. This is the only randomized study to evaluate this compound in children and young adults, and we hope to have the study completed and reported within the next year. The long-acting G-CSF continues to appear to be at least equivalent to the standard compound. The COG Ewing's Biology study AEWS02B1 opened in January of 2003, and we continue to receive specimens as a major center participating in this study. Data are just beginning to be generated on this study. We have recently begun a study using matched related allogeneic transplant for patients with recurrent Ewing's sarcoma and rhabdomyosarcoma. To date six patients have been treated. Based upon discussions with colleagues at St. Jude's Children's Research Hospital, we are exploring the possibility of collaborating with them in developing a haplo-identical transplant study in similar patients which would allow more patients to be eligible for this approach.